Molecular Basis of Inheritance: NEET questions with solutions

Molecular Basis of Inheritance covers DNA structure and replication, transcription, translation, the genetic code, and gene regulation via the lac operon — the physical, molecular basis underlying Mendelian genetics. NEET draws heavily on the classic DNA-as-genetic-material experiments (Griffith, Hershey-Chase, Meselson-Stahl), the precise properties of the genetic code, and applications such as DNA fingerprinting. Marks are commonly lost by confusing the template strand with the coding strand, or continuous (leading strand) with discontinuous (lagging strand, Okazaki fragments) replication.

1. 1.The two strands of a DNA double helix are held together by hydrogen bonds between complementary nitrogenous bases. A cytosine on one strand…Structure of DNAEasySingle correct
2. 2.The two polynucleotide strands of a DNA double helix run in opposite directions, one 5'→3' and the other 3'→5'. This arrangement of the two…Structure of DNAEasySingle correct
3. 3.In Frederick Griffith's experiment, mice injected with a mixture of heat-killed S-strain (smooth, virulent) Streptococcus pneumoniae and…The Search for Genetic MaterialMediumSingle correct
4. 4.Hershey and Chase used bacteriophages labelled separately with radioactive sulphur (³⁵S) and radioactive phosphorus (³²P) to infect E. coli…The Genetic Material is DNA — Hershey-Chase experimentMediumSingle correct
5. 5.E. coli cells were grown for many generations in a medium containing only the heavy nitrogen isotope ¹⁵N, so that all their DNA became fully…Replication — Meselson-Stahl experimentHardSingle correct
6. 6.DNA polymerase can add nucleotides only in the 5'→3' direction. Because the two template strands at a replication fork are antiparallel, one…Replication — enzymes and Okazaki fragmentsMediumSingle correct
7. 7.RNA polymerase transcribes only one strand of a DNA segment, even though the DNA is double-stranded. Read the Assertion and Reason below on…Transcription UnitHardAssertion–Reason
8. 8.Two statements about the genetic code are given below. Which one/ones is/are correct?Genetic CodeMediumStatement based
9. 9.Consider the following statements about regulation of the lac operon in E. coli. Which one/ones is/are correct?Regulation of Gene Expression — the lac operonMediumStatement based
10. 10.DNA fingerprinting relies on comparing regions of the genome that show a high degree of polymorphism (variation) between individuals. Which…DNA FingerprintingEasySingle correct